How To - B9 Heavy SSTO

[BadManiac]

I'd like some advice/inspiration for building a heavy SSTO with B9 parts. I've been trying to build one capable of getting the classic orange tank to 100KM LKO. I'd like a reusable launch vehicle for larger payloads for interplanetary missions. But so far I haven't had any luck. Building SSTO's I can do. But after a certain point It takes more fuel to just get the added weight of that fuel into space that it just no longer is capable of SSTO, my current design is a delta wing bi-plane design with 7 turbo jets and 2 rockets. It gets to 1200m/s at around 20KM but then fails to lift that last bit into orbit when I switch to the rockets.

So does anyone have any ideas, advice or screenshots of their working B9 heavy SSTO?

[Gauss H2K]

Aren't the B9 SABREs essentially made for SSTO's? Why not use them, and save some weight since those turbojets become dead weight after 20km, and the rockets are deadweight before that. Also you might try adding more intakes, 20km is high, but not high enough. I would also aim for 1.4-1.5 km/s at 25km before switching to rockets.

[Hodo]

Here is a thread of my SSTOs, most of which are using B9 parts.

http://forum.kerbalspaceprogram.com/threads/56945-Hodo-Creations-SSTO-craft-designs-and-files-for-those-who-want-them

And here are some of my older still functional Heavy lifters using B9 parts.

SP-400A

over 60 ton lift capacity (2 orange tanks)

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And the SP-406

over 90 ton (3 orange tanks)

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SVO-18

VTOL, SSTO one fuel load to the Mun, not back though... had to send a ship to refuel them there.

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SVO-25

VTOL SSTO, 25 ton lift capacity.

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The trick is finding that balance point for the cargo, and managing to get it to fit. The power is the easy part, most of my SSTOs that I have made have a TWR of over 1.5:1.

You can use SABRES, they are good, but really not that efficient. For long haul cargo runs I actually make sure to only use the SABRE rocket to push it to orbital speeds after that I turn it off. Most of my earlier SSTOs didn't use SABREs. Tubrojets are fine up to mach 3.5+ then they start to die off. So the trick is to get up to around 25km, slowly while accelerating as fast as you can. Most of my ascents take upwards of 10mins, I climb out of the lower thick atmosphere as fast as possible, usually at 45deg nose up, once I am at 12-15km I bring the nose down to 20deg and continue to accelerate until I hit 25km. If I have designed the aircraft right it should get to mach 5 before I have to switch over to rockets.

I prefer LV-Ns for the boost stage if possible, but you can use what ever is lightest and most efficient. LV-Ns are heavy and weak but great for fuel.

Edited March 13, 2014 by Hodo